Modern Britain has come a long way in its approach to national security issues since prime minister Harold Macmillan told MPs in 1963 that it was "dangerous and bad for our general national interest to discuss these matters." Fifty years on, much has changed. The security and intelligence services now have a statutory existence which makes them proper subjects of public interest. The cold war is over and the threats to the post-Westphalian nation state come from terrorist cells and loners, not enemy states and armies. Meanwhile, the technologies of surveillance and record-keeping have been transformed out of recognition. The era of steaming open envelopes and even of phone-tapping has been supplanted by the mass collection of metadata in the NSA's Prism project in the United States and by GCHQ's Tempora programme here.

Two things in the approach are relatively unchanged, however. The first is the state's appetite for information about perceived enemies. This appetite is as insatiable in peacetime when confronted with jihadist cells as it was in wartime when facing Hitler's Wehrmacht. The difference between then and now, however, lies in the capacity of modern technology to gratify that appetite. The other unchanged factor is the continued reluctance of the security and intelligence services to be meaningfully accountable, not just to the general public, where obvious practical limits apply, but even to the rest of government.

No one should deny that modern Britain faces a national security threat, nor deny that this challenge raises difficult issues for any liberal democracy. The Guardian's NSA and GCHQ reporting fully acknowledges this. But the reporting also exposes what a bad job Britain is doing to keep the necessary work of the secret arms of the state within properly accountable bounds. The contrast with the United States, where the president has acknowledged the legitimacy of debate and Congress is currently scrutinising three pieces of surveillance and data reform legislation, is acute.

Three genuinely important recent pieces of testimony have now brought the scale of our accountability deficit into focus. The first is the former cabinet minister Chris Huhne's revelation that the government's National Security Council, supposedly the senior executive arm of government in security matters, was never briefed about Prism or Tempora. The second is the charge by the former director of public prosecutions Lord Macdonald that parliamentary oversight is "sickly" and that the chair of the intelligence and security committee, Sir Malcolm Rifkind, is badly compromised in his oversight role because he is an ex-foreign secretary formerly responsible for MI6.

Here, therefore, is the pressing problem that faces Britain's political leaders. Our security services practice mass collection of communications metadata which, as an NSA official admits, "tells you everything about somebody's life", terrorist or not. Neither the cabinet nor the parliamentary oversight, nor the legislative committee looking into snooping laws, has provided real accountability over such sweeping activity. In this, as in other respects, the security services enjoy a degree of legal and operational autonomy that exceeds what many MPs and ministers, if they knew about it, would judge appropriate. The head of MI5 says such discussion helps the nation's enemies. That is untrue. It is the unregulated surveillance that poses a threat to the nation, along with the threat from our enemies. Parliament urgently needs to exert a proper grip and to find a better balance. Starting now.